How Do You Know If You Have Brugada Syndrome?

What is a diagnosis of Brugada syndrome?

Brugada syndrome is a rare and sometimes fatal heart rhythm disorder. Brugada syndrome causes irregular heartbeats in the heart's lower chambers (ventricles), called ventricular arrhythmia. If left untreated, the irregular heartbeats can cause serious complications and even death. Because complications usually occur when a person is at rest or asleep it is considered a type of sudden unexplained nocturnal death syndrome (SUNDS).

Some patients with Brugada syndrome may be asymptomatic, but a routine electrocardiogram (ECG) will show the ventricular arrhythmia and changes in the normal electrical waves on an ECG, specifically ST-segment elevation in leads V1-V3.

Symptoms of Brugada syndrome include:

• Lightheadedness and fainting
• Heart attack, often during sleep or rest
• Nightmares or thrashing at night
• Associated atrial fibrillation
• Fever – may be a trigger for symptoms

Brugada syndrome is typically a genetic disorder that is passed on in families. Mutations in certain genes result in abnormal heart rhythms.

The SCN5A is a gene responsible for providing instructions for the cardiac sodium channel, which serves to transport positively charged sodium atoms (ions) into heart muscle cells. In about 30% of cases, this gene is damaged (mutated). Other genetic mutations that cause disruption in the proper flow of ions through sodium, calcium, and potassium channels in the heart muscle can also impair the heart's normal rhythm.

In some cases, Brugada syndrome may be acquired and the cause is unknown. Some known causes that are not due to genetic defects may include:

• Medications that can alter heart rhythm
  • Drugs used to treat chest pain (angina)
  • Antihypertensives used to treat high blood pressure
  • Antidepressants
  • Drugs to treat mental illness
• Abnormally high blood levels of calcium (hypercalcemia) or potassium (hyperkalemia)
• Unusually low potassium levels (hypokalemia)

Brugada syndrome is usually diagnosed by identifying certain abnormal heart rhythm patterns on an electrocardiogram (ECG or EKG). During an ECG, electrodes are attached to the chest that measures electrical signals from the heart. 

Genetic testing for a mutation in the SCN5A gene may be done. Often this is performed on family members of patients with Brugada syndrome to see if they have the mutation, or it may be done post-mortem in a person who has died suddenly.

Blood tests may be ordered to help diagnose Brugada syndrome including:

• potassium and calcium levels
• CK-MB and troponin levels

Imaging tests that may be used to help diagnose Brugada syndrome include:

• Echocardiography 
• Magnetic resonance imaging (MRI)

In patients with no symptoms, only lifestyle changes that can help prevent a sudden cardiac arrest may be recommended, such as:

• Avoiding certain drugs that can increase the risk of an irregular heartbeat
• Avoiding alcohol
• Treating fevers promptly (fever can be a trigger for arrhythmias)
• Avoiding activities that cause elevated heart rate, such as competitive sports

In patients who are symptomatic, an automatic implantable cardiac defibrillator (ICD) may be implanted to prevent ventricular tachycardia and fibrillation and sudden death. This is a device implanted under the skin that monitors heartbeats and if the heart starts to beat abnormally, it administers a small electric shock to jolt the heart back to a normal rhythm. 

Drug therapy for Brugada syndrome includes antiarrhythmic medications such as quinidine and amiodarone (Nexterone, Pacerone).

Radiofrequency catheter ablation for Brugada syndrome is a newer treatment that shows promise. 

If Brugada syndrome is untreated, the irregular heartbeats can cause fainting (syncope), seizures, and difficulty breathing, often when an affected person is resting or asleep. Sudden death is the most serious complication of Brugada syndrome. It usually happens unexpectedly, while a person is sleeping. 

Complications of the use of an implantable cardiac defibrillator (ICD) may include:

• Unnecessary shocks
• Infection
• Bleeding

Life expectancy for Brugada syndrome depends on early diagnosis and treatment. Brugada syndrome may be a major cause of sudden cardiac death in men under 40. People with Brugada syndrome on average die between the ages of 26 to 56 years, with an average age of 40 years. If treated appropriately, patients can have a normal lifespan.

It is thought that Brugada syndrome may explain some cases of sudden infant death syndrome (SIDS), a major cause of death in babies younger than 1 year that is characterized by sudden and unexplained death, usually during sleep.